This invention relates to a displacement body of the type for forming cavities in concrete structures in the shape of at least one hollow section, said displacement body comprising a wall determining the contours of said cavities, to a structure formed with employ of such displacement body, and to a method for making a displacement body.
Displacement or filler bodies of widely varying materials are generally used for forming concrete structures with cavities. Widely employed for instance are displacement bodies made of lightweight concrete, fired clay, compressed wood fiber material, plastic extrusions or foamed plastics. Each one of these materials has at least one disadvantage, however; it may be too expensive, too fragile for withstanding rough handling at a building site, too complicated to manufacture, too heavy or not stable enough for certain purposes.
Known from DE-OS No. 26 31 707 is a displacement body assembled of extruded sections of a thermoplastic resin by means of connecting pieces. The interior of the hollow body has to be provided with reinforcing struts for achieving the required strength. In addition, engagement profiles are formed along the outer longitudinal edges of the sections for engagement with the connecting pieces. Displacement bodies of this type are of rather involved construction and thus correspondingly expensive to make. The employ of these displacement in making concrete structures or the like requires additional time and labour for connecting individual profiles to each other by means of the connecting pieces.
Concrete structures having cavities formed with the aid of hollow bodies are known for instance from DE-OS No. 25 36 731. In these structures the displacement bodies consist of approximately cubic injection-molded plastic bodies disposed in spaced arrangement with their open sides facing downwards.
A further disadvantage of this type of plastic displacement bodies is that the costs of the finished structure are unnecessarily increased, as they have to be made rather thick-walled or provided with reinforcing struts for stability reasons. The manufacture of these displacement bodies is moreover restricted to specialized manufacturers equipped for this purpose.
From DE-OS No. 25 03 132 it is also known to reinforce shuttering panels by spot-welding construction steel mats to their side facing away from the concrete to be poured. This permits the thickness of the shuttering panels to be considerably reduced without sacrificing any of their strength, so that they may be made of thin metal sheets. Displacement bodies of this construction are not known, however.